KAD300's Strange one.....

N

nicho

RIP
Joined
19 Feb 2002
Messages
9,265
Location
Home - Midlands, Boat - South Coast
Visit site
KAD300\'s Strange one.....

Running the engines the other day (KAD300's) tethered to the marina berth, I set them (in gear) at 1100 rpm to warm up. 15 minutes later I put one astern, the other forward (someone suggested I could increase the revs that way without straining the lines too much - first time I've tried this) and went for more revs. Pushing the EDC throttles further, one forward, one astern, to increase from 1200 rpm, nothing happened. I pushed further, and suddenly the compressors cut in, and the boat lurched forward trying to pull itself off the pontoon!! SWMBO down below uttered various abusive words as she went flying!. I tried several other times with the same result

Could this be due to it being tethered? Once the ice has melted from the marina, I'll take it out to see if it's OK in normal forward motion, but could the increased pressure on the props caused by being stationary cause this?

Anyone any ideas, or come across this before?
 
Re: KAD300\'s Strange one.....

Press EDC button 'N' for neutral then they will rev to 1500 rpm.

In gear one forward one back the boat will try to turn so surely putting strain on the cleats.
 
Re: KAD300\'s Strange one.....

Hi without wishing to sound rude, what an incredibly brave/STUPID THING TO DO,what point does it serve,you are very lucky given the power from those engines that nothing more serious happened,please don't do it again,regards m m 1.ps again this is not meant to be rude,i am shocked @your question. /forums/images/graemlins/shocked.gif
 
Re: KAD300\'s Strange one.....

I had a KAD32 on my last 2 boats which sit on trailers. When I take the boats out it's always easier to drive up on the trailer. To get the boat up that last little bit I always needed to 'blip' the throttle to give a little boost.

I found with the KAD32 (obviously the same as you now) I had to be VERY careful because you'd keep pushing the throttle but nothing would happen, then all of a sudden the chargers would kick in and you'd get an almighty rush of power. It took a lot of practise to get right... do it wrong and your boat will end up stuck in the boot of the jeep towing the trailer.

It's a funny one, don't know why the engines react this way (my merc 1.7 diesel never did, and petrols dont) - Maybe the engine senses extra resistence from the props, hence into the crank and doesn't accelerate for 'safety' reasons - who knows?

Safe boating
 
Re: KAD300\'s Strange one.....

[ QUOTE ]
but could the increased pressure on the props caused by being stationary cause this?


[/ QUOTE ]

Yes!
Don't break the pontoon /forums/images/graemlins/blush.gif
I sometimes run mine in gear attached to the pontoon, but only up to 1000rpm.

dv.
 
Re: KAD300\'s Strange one.....

I was wondering why he did this too !
What was the overall view about this running of the engines at all?
I thought one conclusion I had come across was that, if anything, it was probably detrimental.
 
Re: KAD300\'s Strange one.....

[ QUOTE ]
Hi without wishing to sound rude, what an incredibly brave/STUPID THING TO DO,what point does it serve,you are very lucky given the power from those engines that nothing more serious happened,please don't do it again,regards m m 1.ps again this is not meant to be rude,i am shocked @your question. /forums/images/graemlins/shocked.gif

[/ QUOTE ]

This is common practice during the winter, although probably best done againest concreted in bollards. There was even an article in MBM several years ago recommending doing this, I've done it for as long as I can remember but obviously only up to about 1500rpm and you can't just walk off and leave it.
Although I can understand the H&S brigade would see it has highly dangerous, as is anything to do with boating I guess.
 
Re: KAD300\'s Strange one.....

[ QUOTE ]
Press EDC button 'N' for neutral then they will rev to 1500 rpm.

In gear one forward one back the boat will try to turn so surely putting strain on the cleats.

[/ QUOTE ]

Yep, they do that with no problem at all.
 
Re: KAD300\'s Strange one.....

Generally what I do is run the engines in Neutral for about 3-5min while I tidy the cockpit/get ropes ready

Then about 10 mins in gear at anywhere between 1000 - 1300RPM, then it's fun time /forums/images/graemlins/smile.gif

Remember that the temp reading on your dash is the coolant temp, not oil temp. It's oil temp that's important to really tell you when your engine is warm.

I installed oil temp sensors on my cars, haven't bothered on the boats as the sump bolt is a pain in the hole to get to. Instead I just cruise slowly for about 10 mins, nicely warm by then
 
Re: KAD300\'s Strange one.....

[ QUOTE ]
Hi without wishing to sound rude, what an incredibly brave/STUPID THING TO DO,what point does it serve,you are very lucky given the power from those engines that nothing more serious happened,please don't do it again,regards m m 1.ps again this is not meant to be rude,i am shocked @your question. /forums/images/graemlins/shocked.gif

[/ QUOTE ]

Point taken, and it was a bit of a shock to me too (and was not what I expected!). It revved very quickly to around 1600rpm before I very quickly shut down the throttles. I was expecting a normal smooth increase in power, but nothing happened for a couple of seconds, then "bang" she lit up!

It's very well tethered for the winter with doubled up sturdy lines, and would have gone nowhere without the entire pontoon following.!

The"one forward, one astern" method of being able to run both engines at higher speeds (one thrust cancels out the other) is something which is used by engineers (or so I'm told) when they need to run engines at higher speeds whilst tethered.

Personally, I'll give the method a miss in future!
 
Re: KAD300\'s Strange one.....

[ QUOTE ]
Generally what I do is run the engines in Neutral for about 3-5min while I tidy the cockpit/get ropes ready

Then about 10 mins in gear at anywhere between 1000 - 1300RPM, then it's fun time /forums/images/graemlins/smile.gif

Remember that the temp reading on your dash is the coolant temp, not oil temp. It's oil temp that's important to really tell you when your engine is warm.

I installed oil temp sensors on my cars, haven't bothered on the boats as the sump bolt is a pain in the hole to get to. Instead I just cruise slowly for about 10 mins, nicely warm by then

[/ QUOTE ]

Yes, I understand that, and with a 45 minute run to the sea at 6/7 kts for us, everything is fully warmed up before hard use!!

An interesting point though, in the middle of Winter, we get into our diesel cars and drive of without waiting for temperatures to rise with no apparant damage. However, when flying, I always wait for oil temperature to reach the optimum before taking off.
 
Re: KAD300\'s Strange one.....

[ QUOTE ]
I was wondering why he did this too !
What was the overall view about this running of the engines at all?
I thought one conclusion I had come across was that, if anything, it was probably detrimental.

[/ QUOTE ]

You can ask a dozen engineers this question, and get a dozen different ansewrs!

The most recommended method seems to be to ensure the engines are run under load (ie in gear) until they are warm, though others reckon this causes condensation in winter and corrosion as a result. Another train of thought seems to be to run them regularly but just for a minute to circulate the oil.

Personally, over winter months I run mine once a month , in gear, USUALLY at just 1100 rpm!!

Interesting to see someone else uses the "one forward, one astern" method - I was certainly given to understand it is quite widespread.
 
Re: KAD300\'s Strange one.....

[ QUOTE ]
[ QUOTE ]

Personally, over winter months I run mine once a month , in gear, USUALLY at just 1100 rpm!!

[/ QUOTE ]

Personally, id rather not run them at all than do that. I'm not saying it's right or wrong, just personal preference.

If my boat is in the water, she gets a good 20 min spin up the river (warm up, then cruise on plane, then WOT for 2-3 min) at least once every 2 weeks - I say i'm just doing it for the engine but in all honesty i'm just feeding my habit /forums/images/graemlins/tongue.gif
 
Re: KAD300\'s Strange one.....

I think the VP manual says run them hot every 2 weeks to keep the engines ok or maybe its just to keep the rust away.
 
Re: KAD300\'s Strange one.....

[ QUOTE ]
I think the VP manual says run them hot every 2 weeks to keep the engines ok or maybe its just to keep the rust away.

[/ QUOTE ]

Don't think the engine would ever get up to full operating temprature at less than 1500rpm - but again, open to correction (I'm talking about oil, not just coolant)
 
Re: KAD300\'s Strange one.....

They will as long as the thermostats work, they will even get there at tickover but that takes longer and I understand is not good for the engine.
 
Re: KAD300\'s Strange one.....

It is widespread nicho. I run my KAD32's on the pontoon regularly in the winter, one forward one reverse for 15 mins then swap over. Have been up to 1200 revs. Apparently much better to have some load on the engine than running in neutral.

However, I do switch the compressors off first - see post of 10/01/09
 
Re: KAD300\'s Strange one.....

I ran mine the other day in order the change the oil and was suprised how much warmer the guage showed running at idle in gear rather than neutral
 
Re: KAD300\'s Strange one.....

[ QUOTE ]
I ran mine the other day in order the change the oil and was suprised how much warmer the guage showed running at idle in gear rather than neutral

[/ QUOTE ]

It's because the engine is under load, hence doing more work
 
Re: KAD300\'s Strange one.....

[/ QUOTE ]

It's because the engine is under load, hence doing more work

[/ QUOTE ]

Doing more work = burning more fuel = more heat building up etc.....

Would not dare to run over idle @450 RPM on ours as at 1500 RPM we would normally do 12 - 14 knots and is at the peek of teh torque curve.... /forums/images/graemlins/ooo.gif
 
You must log in or register to reply here.

Share this page

Top